Finally, I need a way to handle the submit buttons. They're the most
complex input, because I need to launch a function based on their
values and select a default value, just in case. The cgic library has
a function, cgiFormSelectSingle(), that emulates this behavior exactly.
It requires the list of possible values to be in an array of strings.
It populates an integer variable with the index of the parameter in
the array or uses a default value if there are no matches.

See Resources for information on function pointers.
If function pointers still
baffle you, you can choose the function to run in a switch
statement. I prefer the array of function pointers because it is more
compact, but my older code still makes use of the switch statement.

Database System

MySQL from C is largely the same as PHP, if you're used to that
interface. You have to use MySQL's string escape functions to
escape problematic characters in your strings, such as quote characters
or the back slash character, but otherwise it is basically
the same.
The show_event() function requires me to fetch a single record from
the primary key. All of the error checking bulks up the code, but
it's really three basic statements.
A call to mysql_query() executes the MySQL statement and generates a
result set. A call to mysql_store_result() retrieves the result set
from the server. Finally, a call to mysql_fetch_row() pulls a single
MYSQL_ROW variable from the result set.

The MYSQL_ROW variable can be treated like an array of strings
(char**). If any of the data is numeric and you want to treat it as
numeric data, you need to convert it. For instance, in my
application it is desirable to have the date as three separate numeric
components. Because this data is structured as YYYY-MM-DD, I use
sscanf() to get the components (Listing 6).

escapedname holds the same string as name, with MySQL special
characters escaped so I can insert them into an SQL statement
without worry. It is essential that you escape all strings read from
user input; otherwise, a devious person could take advantage of your
lapse and do unpleasant things to your database.